Updates on Fukushima crisis, Oct 17, 2011

Radioactive strontium has been found in a street gutter in Yokohama, appearing to confirm that the radioactive isotope has spread far beyond districts close to the Fukushima No. 1 nuclear power plant.

Sediment in the gutter in the Okurayama district of Kohoku Ward contained 129 becquerels of radioactive strontium-89 and strontium-90 combined per kilogram, city officials announced on Oct. 14. The results follow an earlier report that deposits of strontium had been found on a nearby apartment building’s rooftop.

“We believe (the deposits) were caused by the disaster at the Fukushima No. 1 nuclear power plant,” a city official said. “We cannot judge potential risks. We want to consult with the central government.”

Radioactive cesium of 39,012 becquerels per/kg was also detected in the sample from the gutter but it is the presence of strontium that makes the Yokohama reports exceptional. There had previously been no reports of strontium contamination beyond 100 kilometers of the Fukushima plant.

Although Kohoku Ward is about 250 kilometers from the Fukushima plant, the concentration found in the gutter is higher than the 77 becquerels per kilogram detected in soil in Fukushima city between April and May.

Dirt at the bottom of a dry fountain in the Shin-Yokohama district in Kohoku Ward was also found to contain 59 becquerels/kg of strontium and 31,570 becquerels per/kg of cesium.

In mid-September, the city took dirt samples from the roof of an apartment building where a local resident had reported radioactive strontium, as well as from the gutter in Okurayama and the fountain in Shin-Yokohama. A private lab was commissioned to analyze the data.

Although the city did not reveal the measurements from the apartment roof, saying it did not have permission from the occupants, the resident who filed the initial report said the city found 236 becquerels of strontium per kilogram.

Dirt from the contaminated locations has since been removed and radiation levels in the atmosphere around the gutter in the Okurayama district have fallen to 0.13 microsievert per hour from 0.91 microsievert per hour, city officials said on Oct. 14. Atmospheric radiation at the fountain in Shin-Yokohama has fallen to 0.09 microsievert per hour from 0.13 microsievert per hour.

Explaining the concentration of radioactive materials in particular areas, a city official said: “Dirt and water are likely to gather and accumulate in those spots. We would like to decontaminate such areas.”

Dozens of bottles and test tubes emitting high radiation levels that were found Thursday in a house in Setagaya Ward, Tokyo, contained a white powdery substance believed to be radium-226, which can be used as luminous paint, the science ministry said Friday.

Some of the bottles and test tubes were labeled “Nihon Yako,” which could be the name of a luminous paint company, according to the ministry. “Yako” means luminous.

The bottles were removed from the premises Friday afternoon and will be stored by a radioactive isotope disposal agency, the ministry said.

Despite the initial fear in the neighborhood that the high radiation levels were coming from radioactive materials emitted by the Fukushima No. 1 nuclear plant, the bottles and test tubes had been sitting underneath the floor boards of the vacant house in the Tsurumaki district, the ministry said.

A radiation level of 600 microsieverts per hour was measured around the surfaces of the bottles, which had been contained in a wooden box.

At 1 meter from the bottles, the reading was 20 microsieverts per hour, science ministry official Takao Nakaya said.

After the ministry officials locked the bottles and tubes into a lead container, the radiation level declined to between 0.1 and 0.35 microsievert per hour, he said.

The owner of the house, an elderly woman who is reportedly around 90 years old, said she had never seen the bottles before and had no idea why they had been stored under the floor, according to the science ministry.

The woman’s deceased husband was an office worker and had nothing to do with radioactive isotopes, the ministry said. The woman lived in the house from around 1953 to February this year but now lives elsewhere.

She lived alone in the house since after her husband died a decade ago. According to the ministry, the owner’s daughter has been checking the home now and then for the past few months.

Although the ministry estimated that the woman may have been exposed to about 30 millisieverts per year, no ill effects from radiation have been confirmed. The calculation was made based on an estimate that the woman had slept in a bed about 2 meters away from the bottles. Experts say that when a person is exposed to 100 millisieverts of radiation, the risk of dying from cancer increases by 0.5 percent.

Radium-226, which in the past was used as luminous paint, has an extremely long half-life — 1,600 years — and emits gamma, alpha and beta rays, said Masahiro Fukushi, a professor of radiation at Tokyo Metropolitan University.

Although alpha rays and beta rays can be blocked by a paper or metallic plate, gamma rays are very powerful and penetrate most materials.

When radioactive radium is ingested or inhaled, it accumulates in bones, and thus can lead to cancer, Fukushi said.

In Japan, the radiation hazard prevention act stipulates that a person or an organization must register with the government when storing substances that contain 10 becquerels per gram of radioactive materials and when the total amount exceeds 10,000 becquerels.

However, unregistered radioactive materials are found at an average of about once a year, mostly in shuttered hospitals or abandoned offices, according to Nakaya of the science ministry.

Radioactive cesium found in plankton off N-plant (NHK, Oct 16) High concentrations of radioactive cesium have been found in plankton from the sea near the Fukushima Daiichi Nuclear Power Plant.Researchers from Tokyo University of Marine Science and Technology collected plankton in waters up to 60 kilometers from the coast of Iwaki City in July. They found 669 becquerels per kilogram of radioactive cesium in animal plankton from waters 3 kilometers offshore.They say a wide range of fish feed on animal plankton and that the contamination could accumulate in the food chain and have a more serious impact when it gets into relatively large fish.The research group’s leader, Professor Takashi Ishimaru, says the plankton were so heavily contaminated because sea currents continuously carried contaminated water southward from the nuclear plant. He says detailed studies are needed to determine how long the effect on fish will continue.Study: Fukushima storage pool was vulnerable to aftershocks(Asahi, Oct 15)

Aftershocks of the March 11 Great East Japan Earthquake could have significantly worsened the crisis at the Fukushima No. 1 nuclear plant in the weeks after the disaster, according to a government simulation.

The storage pool in the No. 4 reactor, which had its building’s roof blown off after a hydrogen explosion on March 15, was vulnerable to an aftershock and might have started leaking radioactivity within three hours of a hypothetical aftershock, the study found.

Tokyo Electric Power Co., operator of the plant, initially said the pool was sturdy enough to withstand aftershocks, but Japan Nuclear Energy Safety Organization analysis completed at the end of June but only released on Oct. 14 says radioactive substances could have been discharged 2.3 hours after a temblor knocked out the pool’s cooling system.

The simulation, part of a 300-page report commissioned by Japan’s Nuclear and Industrial Safety Agency, was based on the assumption that the pool would lose cooling water if it was cracked by an aftershock. After the uncooled fuel rods reached 900 degrees and damaged their casings, radioactive leaks would have begun, according to the study.

It said the fuel rods would have begun melting as the temperature hit 2,800 degrees, 7.7 hours after the hypothetical loss of cooling functions.

The storage pool is in the upper part of the No. 4 reactor building and contained 1,331 spent fuel assemblies and 204 new fuel assemblies. TEPCO completed work to reinforce it in July.

The simulation is one of 39 analyses in the report, which is now available at the Japan Nuclear Energy Safety Organization website.

“… 113 people who attended the first workshop for business operators on the basics of decontaminating materials in areas outside the “no entry” zone, which is within a 20-kilometer radius of the crippled Fukushima No. 1 nuclear power plant. Participants included those in the construction, painting and cleaning industries.

The workshop, held on Oct. 4 and 5 in Koriyama, was designed to train local personnel who can join the decontamination operations of the central government and local governments, which will shift into full gear next year.

“The decontamination operation encompasses broad areas,” said an official with the Fukushima prefectural government, which organized the program. “We want to carry it out by utilizing the private-sector force because the task is too enormous to be handled by the public sector alone.”

The program is also intended to offer employment opportunities to people who have been out of work since the March 11 Great East Japan Earthquake, tsunami and nuclear crisis dealt a serious blow to the local economy.

Katsuji Yoshida, a construction company employee, said he joined the workshop at the request of his employer. …

The prefectural government received more than 1,000 applications for the first five workshops within a few days after it publicized the program in early September.

The participants were selected on first-come first-served basis.

But prefectural officials received so many phone calls asking for a chance to attend a workshop that they plan to continue the program into next year.”

Mongolia abandons nuclear waste storage plans, informs Japan of decision The Mongolian government told Japan government officials and others concerned in late September that it had decided to abandon its plans to cooperate with Tokyo and Washington and build facilities to temporarily store and dispose of nuclear waste, it was learned on Oct. 14.Mongolia appears to have judged the plan unfeasible because of opposition movements in the country.It is the latest turn of events that underscores the difficulties in carrying out international projects to build nuclear waste storage facilities. A similar project was also abandoned in Australia in 2002 due to strong public backlash.IAEA team: limit decontamination

By KAZUAKI NAGATA

Staff writer

A research team from the International Atomic Energy Agency submitted a report to the government Friday that commends Japan’s decontamination efforts but suggests that attempting to remove radiation from every affected area would be counterproductive.

In short, they said trying to gather overly radioactive debris, soil and foliage from the Fukushima No. 1 nuclear plant crisis will only result in a highly toxic accumulation in need of disposal.

Japan was praised for its swift efforts to gauge the contamination with priority on children’s health, with parents, volunteers and municipal authorities joining to remove contaminated soil in schools and monitoring cleanup work.

Yet the team, which came on Oct. 7 and was to leave Saturday, advised against being overly cautious in the future decontamination process, as this will impose unnecessary costs.

Their report points out that people should focus less on contamination levels and more on the amount of exposure.

“This investment of time and effort in removing contamination beyond certain (so-called optimized levels) from everywhere, such as all forest areas and areas where the additional exposure is relatively low, does not automatically lead to reduction of doses for the public. It also involves a risk of generating unnecessarily huge amounts of residual material,” the report said.

TOKYO (Kyodo) — Many elementary and junior high schools in the city of Fukushima limit the time their students spend outside school buildings despite completion of soil decontamination, as parents continue to voice health concerns, local education board officials said Saturday.

Of the city’s 72 public elementary and junior high schools, only 14 allowed their students to freely engage in outdoor activities as of Sept. 20, even after the removal of surface soil from schoolyards tainted by radioactive substances originating from the crippled Fukushima Daiichi nuclear power plant, they said.

The city told the schools to allow students to go outside as normal on Sept. 1 after airborne radiation had fallen to safe levels.

With many parents worried about their children’s exposure to radiation at school and elsewhere, the government needs to demonstrate reliable safety standards, an official with the city’s board of education said.

Construction of the cover — composed of 62 polyester fibre sections — began in August to reduce the amount of radioactive materials escaping into the outside environment. With the cover now finished, TEPCO will install air scrubbers inside the reactor building to clear out airborne radioactive substances.

Once the scrubbers are in place, they are expected to process all the air in the enclosure — a volume of about 40,000 cubic meters — every hour, reducing airborne radioactive materials by 90 percent.

The new cover will last for two years. TEPCO is also considering replacing the cover with a stronger one should the firm decide to remove the fuel from the reactor. TEPCO plans to build similar covers over the No. 3 and 4 reactor buildings, which were also destroyed by hydrogen explosions in March.

TEPCO also released video taken by a robot on the No. 1 reactor building’s first floor. The video showed there was no longer steam rising from below ground in the building, but the robot detected extremely high radiation emissions of 4,700 millisieverts per hour.

TOKYO (Kyodo) — A visiting Belarusian scientist, who has offered advice to residents affected by the 1986 Chernobyl nuclear disaster, said Wednesday that he believes Japan’s food radiation limits have been set too high and urged the nation to lower them to realistic levels.

Vladimir Babenko, deputy director of the Belrad Institute of Radiation Safety in the former Soviet republic, told a press conference in Tokyo that he cannot understand the thresholds designated by the Japanese government for food and beverage products, saying they are much higher than Belarusian standards.

Babenko also criticized the Japanese government for its failure to set special standards for children to better protect them from internal radiation exposure.

For example, he pointed out that the limit for radioactive cesium in 1 kilogram of drinking water is set at 200 becquerels in Japan, 20 times as high as the maximum allowable level in Belarus.

The scientist is visiting Japan to promote the Japanese translation of his book about radiation protection. He is scheduled to make a speech in Fukushima Prefecture on Friday.

The booklets had been completely revised, as previous versions were criticized after the outbreak of the crisis for including inappropriate descriptions of nuclear power plants and atomic energy.

However, the latest material contains little information regarding the nuclear crisis and concrete measures to deal with it.

Middle schools have not taught about radiation for 30 years, and how schools use the supplementary materials will be a key issue in teaching about radiation at schools.

The beginning of the booklet for primary school students says, “After the nuclear accidents occurred, materials that emit radiation leaked from the nuclear power plant.”

But it does not mention the nuclear crisis in the main text.

According to the ministry, some of the 13 authors of the booklets said they should describe the crisis, including conditions in Fukushima Prefecture. However, most insisted it was more important to first provide information to students about radiation, so they would understand how disaster-hit areas were contaminated.

The booklets, for example, write that radiation is constantly present in the natural environment and explain about units such as sieverts and becquerels. They also explain that radiation is used in various fields such as medicine, agriculture and industry, using many pictures.

They also write that Japanese receive an average of about 1.5 millisieverts of radiation annually from natural sources, and the average individual in the world receives about 2.4 millisieverts annually.

The new material instructs students to keep away from radioactive materials and shorten the time they are exposed to radiation, to protect themselves from radiation.

To prevent internal exposure, the books instruct students to cover their mouths by using masks or other means, and not to eat food the intake of which has been restricted.

Regarding the connection between radiation doses and health, one booklet says, “There is no clear evidence that people develop cancer from radiation doses below 100 millisieverts.

“It is not necessary to worry about radiation doses if the radiation comes from the natural environment or common practices such as an X-ray, but it is important to avoid receiving radiation as much as possible.”

The booklet for primary students writes, “Radiation does not spread from person to person.”

Regarding the damage suffered by Fukushima residents as a result of radiation fears, and students from the prefecture being bullied, a teaching guideline for primary school teachers says, “Bullying and discrimination [due to radiation] should not occur.”

Such instruction is not mentioned in the booklets for students, however.

An essay in the booklet for high school students describes the “risk and benefit” theory that is used in medicine. “When people use something for their benefit, they cannot avoid a certain amount of risk,” the column states.

This is implying that nuclear power plants bring benefits such as power supply, and risks such as radiation.

“[The essay] seems to be trying to justify the measures taken by the government regarding the nuclear crisis,” said Hosei University Prof. Takeo Samaki, who specializes in science education.

The government’s plan to distribute new supplementary material on energy to schools, focusing on the basics of radiation, is receiving mixed reactions.

The Education, Culture, Sports, Science and Technology Ministry is replacing earlier supplementary booklets on the same subject for primary, middle and high school students. It instructed schools not to use the previous booklets following the nuclear accident at the Fukushima No. 1 nuclear power plant, after learning they included improper descriptions about nuclear power plants.

“As the [new] supplementary material was created by the education ministry, we can use it in classes without worries,” said Shiro Hayashi, 63, principal of Takinogawa Primary School in Kita Ward, Tokyo.

In May, the school’s sixth graders listened to a lecture about radiation given by an official dispatched from the Japan Science Foundation in Tokyo.

After learning from reports that victims of the nuclear disaster forced to take shelter experienced discrimination, the school decided to hold the lecture to give students more precise knowledge about radiation.

Before producing the new booklets, the government had not provided materials about radiation for primary school students, considering the subject inappropriate for them. After the accident at the Fukushima No. 1 nuclear power plant, the school tried to find study material about radiation on the Internet.

“It was hard to find material that explains radiation understandably from a neutral standpoint,” Hayashi said.

As part of new teaching guidelines to be fully implemented in middle schools starting in the 2012 academic year, the science guideline–which refers to radiation studies for the first time in 30 years–was implemented in the 2009 academic year.

Masaki Kobayashi, 51, a teacher of Kaishin Dai-Ichi Primary School in Nerima Ward, Tokyo, plans to teach about radiation in his science class as early as next year.

“As the supplementary material has too much content,” he said, “I’m worried how to teach students about the risks of radiation or how to protect themselves [from radiation] in the limited class time, without leaving them feeling uncertain. Teachers also need to study [about radiation].”

Hisao Oshimizu, 60, principal of Ono Primary School in Okumamachi, Fukushima Prefecture, said: “When children go back to their hometown, knowledge about radiation will become necessary. We’d like to teach about it gradually.” The students of the school evacuated as a group to Aizu-Wakamatsu in Fukushima Prefecture after the nuclear accident.

Watari Middle School, in the Watari district of Fukushima, measures radiation at the school almost every week. The Watari district has shown radiation levels that are relatively higher than elsewhere in the city.

While the school informs the students’ parents of the radiation levels, it refrains from explaining the effects of radiation to students as it believes the word “radiation” would cause stress for some children, the school said.

Yoshinori Saito, 59, principal of the school, criticized the government’s position on teaching about radiation, saying, “The information [in the new supplementary material] should have been distributed to schools before the [Fukushima] accident happened.”

Meanwhile, Hosei University Prof. Takeo Samaki said: “I don’t think schoolteachers will be able to teach about the effects of radiation on human bodies, which is the most important point, because the material does not clearly describe them. “Opinions are divided even among scholars over the bodily effects of a one-time exposure to below 100 millisieverts of radiation. To enable children to make objective judgments, essays expressing various opinions should have been included in the supplementary material,” he said.

IAEA team: limit decontamination (Japan Times) | IAEA: Cleanup of low contaminated areas will be ineffectual(Asahi, Oct 15)”Juan Carlos Lentijo, who leads a team of experts from the Vienna-based International Atomic Energy Agency, told a news conference in Tokyo on Oct. 14 that the Japanese government should weigh the costs and time required to decontaminate against the safety benefits that will be achieved.Lentijo, an expert on decontamination, also said that it would be desirable to begin the cleanup of forests after assessing if the process will contribute to increased public safety.The 12-member team arrived in Japan on Oct. 7 to offer advice on the country’s efforts to deal with decontamination after inspecting the operation under way in areas surrounding the stricken Fukushima No. 1 nuclear power plant.

The team’s report, released on Oct. 14, urged the government to be more realistic about decontamination.

It said the full-scale cleanup of forests and areas where low levels of radiation are detected will be ineffective given the money and time that it will take.

The decontamination operation is expected to cost the central government more than 1 trillion yen ($12.99 billion). …

Analysts say that the central government’s operation could jeopardize similar work undertaken by other entities in terms of manpower and produce an enormous amount of topsoil scraped off from the ground surface.

While the report is nonbinding, the IAEA experts were dispatched at the request of the Japanese government.”Rice farmers plan tough new radiation limits (Japan Times)
Rice farmers near the Fukushima No. 1 nuclear plant will impose radiation safety limits that will only clear grains with levels so low as to be virtually undetectable after government-set standards were viewed as too lenient and sales suffered.

Farmers now completing the harvest in areas affected by fallout from the nuclear station are struggling to find buyers amid doubts about cesium limits, which are less stringent than in livestock feed. No samples have been found exceeding the official limits.

A self-imposed, near-zero limit on radiation in rice may help spur sales from Fukushima, which was the fourth-largest producer in Japan last year, representing about 5 percent of the total harvest. The prefectural office of Zen-Noh, the nation’s biggest farmer group, plans to only ship cesium-free rice to address safety concerns, as does the National Confederation of Farmers Movements, which includes about 30,000 producers nationwide.

“We advise our members to test their rice for radiation and sell only if results show no cesium is detected,” said Yoshitaka Mashima, vice chairman of the confederation. The government has tried to “hide inconvenient information, which is deepening consumer distrust.”

The near-zero limit was set as very low levels of cesium are hard to detect. Testing equipment in Japan is unable to verify levels of cesium in food below 5 becquerels a kilogram, according to Mashima.

The government set the maximum allowed level of cesium in food about a week after the March 11 earthquake and tsunami, based on recommendations from the International Commission on Radiological Protection. The health ministry set the rice ceiling at 500 becquerels a kilogram, while the agriculture ministry’s limit for feed is 300 becquerels.

The agriculture ministry allowed rice planting in Fukushima and neighboring prefectures in April, excluding paddy fields containing more than 5,000 becquerels of cesium per kilogram.

Prefectural governments began allowing farmers to ship their harvest if test results showed samples from their produce did not show cesium exceeding the limit.

Still, rice millers are concerned about buying new crops from areas near the plant as the current cesium standard, applied to brown rice, doesn’t ensure the safety of its byproducts, including bran.

Cesium levels in rice bran, an ingredient used in compound feed for livestock, is about seven times as high as brown rice, said Ryo Kimura, chairman of the Japan Rice Millers and Distributors Cooperative. Because of this, feed makers are reluctant to buy bran made from brown rice that may contain more than 40 becquerels a kilogram of cesium, he said.

Brown rice is polished to produce milled rice for sale to retailers and byproducts are shipped to makers of cooking oil, pickles and animal feed.

Demand for this year’s rice crop has also been weakened as consumers hoarded last year’s crop amid radiation concerns, Kimura said.

Domestic food-rice inventories, excluding the government’s reserve, fell 16 percent to a three-year low of 1.82 million metric tons in June as consumers boosted purchases after the disaster. The volume is equal to 22 percent of Japanese rice demand in the year that ended June 30.

“Consumers who see the current cesium standard as lenient won’t buy rice from polluted areas,” said Nobuyuki Chino, president of Continental Rice Corp. in Tokyo. “Wholesalers are seeking rice that tested negative for cesium as they know grain containing radioactivity, even if the amount is smaller than the official standard, won’t sell well.”

Stockpiles may increase by more than 100,000 tons by next June because of weak demand and a good harvest this year, dragging down prices, Chino said.

Low demand for rice harvested in eastern Japan, affected by radiation fallout from the Fukushima plant, is reflected in a price gap between the Tokyo and Osaka grain exchanges, Chino said.

Rice for November delivery on the Tokyo Grain Exchange settled at ¥14,400 a bag on Wednesday, 4 percent cheaper than the price on the Kansai Commodities Exchange in the city of Osaka. The Kansai exchange trades rice produced in western Japan, while the Tokyo bourse handles rice grown in the east, including Fukushima Prefecture.

The government has been slow to take measures to ease safety concerns as tighter regulation will boost costs for radiation testing, adding troubles as the nation struggles with swelling fiscal deficits, said Naoki Kazama, an Upper House lawmaker from the Democratic Party of Japan.

Stricter control may also increase a ban on shipments of local farm products and cause shortages, sending producers out of business and boosting compensation payments by Tokyo Electric Power Co.

“The government should put a priority on protecting human health, especially of our children,” Kazama said. “Now they are paying consideration to the interests of various parties evenly.”

Kazama has proposed that all foods be tested for radioactive contamination and their radiation levels be labeled.

The health ministry, which rejected the proposal as unfeasible, plans to revise cesium standards in food in line with recommendations from the Food Safety Commission.

An expert panel on the commission compiled a report in July that said more than 100 millisieverts of cumulative effective doses of radiation over a lifetime could increase the risk to human health. The amount doesn’t include radiation from nature and medical exposure, it said.

The current Japanese standard is based on a proposal from the International Commission on Radiological Protection that humans should avoid radiation exposure exceeding 5 millisieverts a year through food and drink consumption.

Local authorities checked a total of 3,989 rice samples in 17 prefectures in the eastern half of Japan by Tuesday, according to the agriculture ministry. The highest level of cesium, or 500 becquerels a kilogram, was detected in crop from Nihonmatsu, about 55 km from the Fukushima nuclear station.

Some food retailers and producers set voluntary ceilings for cesium on their products to alleviate consumer concerns.

Organic food supplier Radishbo-ya Co. in Tokyo set its cesium standard at 20 becquerels a kilogram for milk and water, and 50 becquerels for rice, meat, eggs and vegetables. These are 10 percent of the amounts allowed by the government.

“The government is very slow to take measures against contamination,” said Hiroshi Chikaato, quality director at Radishbo-ya. “That’s why consumer concerns about food safety persist. People who lost confidence in the safety of food produced in the nation’s east are only seeking food from the western areas.”

“Tokyo suffered minimal damage from Typhoon Roke, and only a handful of homes and other buildings were flooded. Although record winds of up to 40 meters per second blew over some big trees in central Tokyo and led to train services being suspended for hours — so stranding thousands of homebound commuters — nobody was killed or severely injured…But what could have happened, if the storm had been more powerful, is a completely different story.

With global warming and the ongoing concretization and asphalting of Tokyo exacerbating the “heat-island” effect, according to experts the city’s chances are greater than ever of being swamped either by typhoons or one of the increasingly frequent “guerrilla storms” that strike suddenly with short but massive downpours in localized areas.That bleak prognostication follows logically from the fact that Tokyo’s current flood-management systems — from river-improvement projects to underground runoff routes and its water gates — are designed to cope with downpours of up to 50 mm per hour. In recent years, however, they have often reached 100 mm per hour.” Read the rest here.